Dimensional analysis MCQ: Identify the pair of physical quantities that do not share identical dimensions. Out of the following pairs, determine which pair has different dimensional formula; assume standard M–L–T system for mechanics quantities. Choose the correct option.
IIT JEE
Physics
Difficulty: Easy
Choose an option
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AWork and torque
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BImpulse and linear momentum
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CPressure and stress
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DPower and energy
Answer
Correct Answer: Power and energy
Explanation
Given data
- We compare dimensions of four pairs under the M–L–T system.
Concept/ApproachUse dimensional formulae: Force = MLT-2; Work/Energy = ML2T-2; Power = ML2T-3; Impulse = change of momentum = MLT-1; Pressure/Stress = ML-1T-2; Torque (moment of force) = ML2T-2.
Step-by-step checkWork vs torque ⇒ both ML2T-2 (identical).Impulse vs momentum ⇒ both MLT-1 (identical).Pressure vs stress ⇒ both ML-1T-2 (identical).Power vs energy ⇒ ML2T-3 vs ML2T-2 (different).
Common pitfallsConfusing torque with power; torque shares dimensions with work/energy, but power includes per-unit-time.
Final AnswerPower and energy